In theory, Russia’s proposal that Bashar Assad relinquish control of his chemical weapons is a diplomatic masterstroke that turns Barack Obama’s foreign policy nightmare into a stunning victory. Talk of a crippled presidency might be replaced with comparisons to John F. Kennedy’s Cuban Missile Crisis triumph. That’s why Obama says he means to take the idea seriously. “We’re going to run this to ground,” Obama told CNN Monday, adding his administration was working to determine whether “we [can] arrive at something that is enforceable and serious.”

Alas, there’s good reason to think they can’t. The idea riveting Washington, Damascus, Moscow and most everywhere in between is so filled with obstacles and pitfalls that it might join the February 2003 plan to send Saddam Hussein into exile with $1 billion as a terrific-sounding idea that falls apart, to everyone’s detriment.

Why is that? Consider some of the chief obstacles to the Russian solution:

Are the Russians Serious? Moscow isn’t just a longtime supporter of Assad. It has shielded him even from the smallest gestures of international condemnation for his alleged use of chemical weapons. In the past two months, “Russia has blocked two resolutions condemning the generic use of chemical weapons and two press statements expressing concern about their use,” United Nations Ambassador Samantha Power said in a Friday speech. Any plan that the U.S. and its allies can support will probably require a U.N. resolution backed up with the explicit threat of military action, something it’s extremely difficult to see Vladimir Putin supporting.

Can Assad Be Trusted? Obviously any plan to secure or remove Assad’s chemical arsenal will require thorough verification. But the process of sending inspectors or security forces to accomplish that task will take time, and Assad will have opportunities to delay and complicate it — perhaps buying himself time in the hope that the world’s attention and indignation will fade. As Roger Cohen of the New York Times noted on Twitter Monday night, Bosnian Serb forces forestalled NATO air strikes in the 1990s by making false promises to hand over their heavy weapons. In the 1990s, Saddam mastered the art of delaying and deceiving U.N. weapons inspection teams.

Is it Logistically Feasible? Last year, the Pentagon estimated that securing the dozens of sites at which Syrian chemical weapons are thought to be stored could take up to 75,000 U.S. troops. A much smaller number (of what would almost certainly will be Russian, and/or United Nations personnel) should be required here, given the presumed cooperation of the Syrian government; they won’t have to shoot their way in. But it’s still a mighty task that could require many hundreds, if not thousands, of trained professionals — plus ample security to protect them: remember that U.N. inspectors were fired upon in Syria earlier this month. “It is a daunting task to get a hold of all these weapons,” deputy national security advisor Tony Blinken told CNN Monday afternoon, “and you probably need a cease-fire.” The odds of that seem awfully small, not least because it would require the fanatical Islamist fighters of al Nusra to agree.

Seriously. How Would This Even Work? Even if trained and armed inspection teams do reach every chemical site, then what? Securing as many as 50 sites for more than a nominal period of time isn’t very practical. But destroying chemical agents safely can take years. A workable option might include moving the chemicals to an easy-to-defend central location in a remote part of the country, but that’s not a simple thing to pull off in the middle of a civil war and in concert with a government that will resent the outside intrusion. Plus, moving Assad’s nerve gas invites the risk of a horrible accident, or an attack by would-be terrorists who want to steal the weapons.

It’s possible these problems are more manageable than they first appear to the likes of Blinken, John McCain and many others. There’s no question that peacefully removing chemical weapons from the Syrian conflict would solve one of the world’s great national security dilemmas more easily than most people dreamed possible.

But it’s also worth considering that, according to Obama himself, Vladimir Putin privately raised this plan with him last week. For reasons Obama hasn’t explained, he apparently chose not to pursue it. Perhaps because he concluded that, as Secretary of State John Kerry put it on Monday, “it can’t be done.”